NTR events are mainly one of two things. Sharing in exchange for free skill training, or if your MC ignores one of his girls for a whole week the villain can make a move on her
That is not true.
There is a timer in the game on how often you can fuck a girl. that timer is set to either 4 or 5 days, i forgot.
if you miss a girl's timer by 1 day and don't fuck her yourself on the day it finally resets then it gives +1 to her netorare variable. this progress does not reset. by the 3rd point she is fucking another guy.
You are also not really warned about the mechanics and there is no in universe choice nor any other way to stop it in universe (except perhaps never missing a single day on the counters which is unreasonably tedious).
Instead you will see the first "sexual harassment but not sex yet" scene, and if you are lucky get the idea to ask online what is going on and how to stop it (special setting).
This is
horrible implementation.
The only realistic way to actually avoid getting cucked in this game is to disable netorare in the hidden special settings menu (not the one called settings in the menu. but the one you bring up by pressing q on the keyboard).